Shook Hardy & Bacon has not admitted liability. However, the 500-lawyer, Kansas City, Mo.-based law firm has agreed to settle for $5 million a bankruptcy trustee’s civil complaint contending that it and an associate attorney aided and abetted a former client’s violations of federal securities law.

The ex-client, Nevin Shapiro, 44, is now a convicted Ponzi schemer, serving a 20-year prison sentence for the securities fraud and money laundering to which he pleaded guilty in 2010. He used his grocery brokerage business, Capitol Investments USA Inc., to solicit some $930 million from investors over a nearly five-year period from 2005 to 2009, according to the Miami Herald (sub. req.) and an FBI press release.

After mediation, Shook Hardy agreed Friday to what was described as a “compromise … to avoid the further expense, inconvenience and burden of protracted litigation,” The judge in the case must approve the agreed settlement before it is final.

Filed in federal court in Miami, the trustee’s suit alleged that associate Marc Levinson, whose expertise was in products liability litigation, became Shapiro’s lead counsel because of a childhood friendship. Levinson, who has been on administrative leave at Shook Hardy since November, allegedly became increasingly concerned in late 2006 about his client’s conduct, requesting a determination from another lawyer at the firm which resulted in a memo saying that Shapiro had violated the Securities and Exchange Act, the newspaper recounts.

A month later, the firm learned that a business associate and an investor had complained to the FBI about Shapiro and helped him retain criminal counsel. However, the firm and Levinson continued to advise Shapiro as he issued millions of dollars worth of promissory notes through 2009, the suit says.